Lamp base



FIG. 1 is a front elevational view of a lamp base showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a top, rear perspective view thereof, the lamp being shown in broken lines for illustrative purposes only. 

The ornamental design for a lamp base, as shown and described. 